Defroster



April 18, 1933. M E HENNING 1,904,658

DEFROSTER Filed Oct. 27, 1932 movable control member.

Patented Apr. 18, 1933 UNITED STATES- PATENT OFFICE PENN ELECTRIC SWITCHOF IOWA DEFROSTER Application filed October 27, 1932. Serial No.639,808.

An object of my invention is to provide a control switch with defrostingmechanism which is simple, durable and comparatively inexpensive tomanufacture and assemble 1n 5 connection therewith.

Another object is to provide in connection with a movable control membermovable through a limited space during controlling operations, a meansfor modifying the 0 operation thereof over any given period of timedesired, such means being selectively operable to modifying ornon-modifying position, as desired and being controlled by a. controldevice already provided for the A further object of my invention is toprovide a control mechanism for refrigerators comprising means forstarting and stopping operation of the refrigerator to obtam normalcycles of operation or permit operation of the refrigerator at apredetermined factory setting and to provide means for securingtemporary modification of the fac tory setting of the refrigerator toobtain diffcrent normal cycles of operation which is usually done by theoperator of the refrigerator or housewife without loosing the factorysetting and to provide means for obtaining non-normal cycles ofoperation of the 0 refrigerator for defrosting purposes, the temporarymodification of the cycles of operation as well as the non-normal cyclesof operation being manually controlled by a common means whereby theoperator or housewife in connection with domestic ref rigeration maysecure normal operation of the refrigerator at temperatures other thanthe factory setting and likewise secure operation of the refrigerator innon-normal cycles for defrosting purposes.

Still a further object is to provide a differential adjusting ormodifying means for a control switch which is controlled by the sameknol) which controls the range, manual stopping and starting orresetting after tripping of the switch to off position by reason of anoverload cutout mechanism, the modifying means including a spring loadedmemher which is associated with the knob for being controlled thereby.

Still a further object is to provide in connectlon with a control membermoved by a power element opposed by a spring, a modifying means whichassists the spring when moved to operative position and adjustingmechanism for the spring being associated with the modifying means tocause it to assist the spring or remain in an inoperative positlonrelative thereto, as desired. With these and other objects in view, myinvention consists in the construction, arrangement and combination ofthe various parts of my device, whereby the objects contemplated areattained, as hereinafter more fully set forth, pointed out in my claims,and illustrated in the accompanying drawing, in which:

Figure 1 is a plan view of a control switch with defrosting mechanismembodying my invention associated therewith, part of the cover platebeing removed from the casing and parts of the mechanism being shown insection to better illustrate the associated parts of the device.

Figure 1A is a partial view of Figure 1 7 showing the parts in adifferent position.

Figure 2 is a front elevation of the switch structure.

Figure 3 is a sectional view on the line 33 of Figure 1; and

Figure 4 is a perspective view of the defrosting lever.

On the accompanying drawing, I have used the reference numeral 10 toindicate generally a switch housing. It has a front plate 12 providedwith a hub 14 in which a control knob 16 is both rotatable and slidabletoward and away from the front plate 12.

With respect to the interior mechanism of the switch structure, anoperating arm 18 has two ears 18a pivoted on a pin 20. The operating arm18 is operated by a pressure or temperature bellows 22 opposed by aspring 24. The left end of the spring 24 is seated in a washer 25. Thewasher 25 has lugs 25a 95 pivoted in forks 18b of the arm 18 (two lugsand two arms being provided for proper balance to prevent binding). Thearm 18 car ries a pointed member 26 engaging one end of an overcenterspring 28, the opposite end 100 of which engages a pointed member 30 ofa switch operating arm 32. The arm 32 has lugs 34 pivoted 1n depressions36 of a frame member 38.

Adjacent the lower wall of the casing 10 in Figure 1, a slidable contactbar 40 is shown. It carries a contact 42 adapted to engage a stationarycontact 44 whereby to establish an electric circuit when the contactsare together. A spring 46 serves to retract the contact 42 from thecontact 44 when the arm 32 permits it to do so.

The tension of the spring 24 is adjustable by the knob 16 which issecured to a sleeve 48. The sleeve 48 has internal teeth 50 engagingserrations 52 of an adjusting screw 54. The adjusting screw 54 isscrewed through a cap 56 which is non-rotatable relative to the easing10.

From the foregoing description, it will be obvious that the switch arm32 is automatically controlled, depending upon pressure in the bellows22.

The switch is primarily designed for controlling a mechanicalrefrigerator and does so by engaging the contacts 42 and 44 when thetemperature rises to a predetermined high degree and separating themwhen it lowers to a predetermined low degree.

Within the adjusting screw 54, a differential adjusting screw 54a isprovided. It is screw-threaded relative to the range adjusting screw 54and its left end serves as a stop for an extension 32a of the switchoperating arm 32. By removing a screw 16a in the knob 16, access can behad to the differential adjusting screw 54a to change its position andconsequently the limit to which the arm 32 can swing in a clockwisedirection, thus changing the difierential of operation of the arm 32.

The serrated tooth connection at 50 and 52 permits a factory adjustmentby removing the screw 16a with the pointer on the knob 16 at any of theindicating numerals on the face plate 12 corresponding to the number ofgraduationsit is desired to change the adjustment. A screw driver or pinis then inserted through the bore of the sleeve 48 and the screws 54 and54a are pushed inwardly against the tension of the spring 24 until theserrations 52 are free of the teeth 50. The knob 16 is then returned tothe defrost position and the spring 24 released whereupon the serrations52 will again seat in the teeth 50 and the range will have been changed,as desired. Thereafter the knob 16 will have the same range but therange will be at a lower setting. To raise the setting by this factoryadjustment, the knob is rotated from the defrost position to the desiredgraduation, while the adjusting screw 54 is pressed inwardly.

Normally the knob 16 can be rotated through the range of numbers from 1to 9 on the face plate 12 in Figure 2 for changing the range ofoperation. The features just described and a manual on and oil" controlas well as a manual overload protection reset control are operated bythe knob 16 and all of these parts are fully disclosed in detail in mycopending application Serial No. 635,974, filed October 3, 1932.

The overload protection feature, briefly, involves a ratchet wheel 58secured to a sleeve 60 which in turn is secured by solder to astationary pin 62. A resistance coil 64 surrounds the tube 60 so thatwhen an overload current flows through the resistance wire, the solderwill be melted whereupon the ratchet wheel 58 can rotate.

The ratchet wheel is engaged by a pawl 66which is operatively connectedwith a trip arm 68 which is moved toward the right when the ratchetwheel 58 rotates. Upon being moved toward the right, the trip arm 68engages a lug 70 on the switch bar 40 for separating the contacts 42 and44.

To reset the overload protection mechanism after it has once trippedout, the knob 16 has a plate 72 thereon engaged in a hook 74 of aslidable plate 76. The plate 76 has an extension 7 6a adapted to engagea second slidable plate 78 and cause it to move the trip arm 68 to aposition permitting the spring 46 to close the contacts 42 and 44.

It will be noted that the slidable plate 78 has an ear 78a and the triparm 68 is pivoted to this ear. A spring 80 serves the purpose ofconstraining the slidable plate 78 toward the right in Figure 1.

\Vhen the plate 76 is moved toward the left, it also moves the pawl 66with it for resetting the pawl in a new position on the ratchet wheel58. Thus the thermal overload cutout is reset by the knob 16.

The plate 72 is also operable to move the plate '7 8 and the trip arm 68toward the right when the knob 16 is pulled outwardly from its positionshown in Figure 1. Thus the knob 16 provides a manual cutout for theswitch structure. When the knob 16 is again pushed inwardly, the tri arm68 moves to the position of Figure 1 w ereupon the spring 46 re-engagesthe contacts 42 and 44.

Dcfrosting mechanism for one end of the spring 82 to engage. The

other end of the spring engages a washer 96 which is in engagement withthe adjusting screw 84.

The screw itself is threaded in the face plate 12 so as to be adjustedrelative thereto.

The cam 86 has the major portion of its periphery formed on a radiusfrom the center of the sleeve 48. A notch 86a is provided in theperiphery and when this is in registry with the extension 90 of the armA, the defrosting mechanism is in defrosting posltion, as willhereinafter be more fully described.

As shown in Figure 1, it will be noted that the controlling arm 18 is inits right hand position and that a flange 18a thereof adjacent the pivot20 is spaced from an edge 90a of the arm A. The arm A is held in thisposition by the peripheral portion of the cam 86 engaging the ear 92 ofthe arm A against the tension of the spring 82.

When the knob 16 is moved to the defrost position indicated on the faceplate in F igure 2, the arm A will drop to the dotted line positions ofFigures 1 and 3. In such position, the spring 82 is effective to loadthe lever 18 against the action of the bellows 22 and thus prolong thecycles of operation of the controlling arm 18 by aiding the tension ofthe spring 24. As shown in Figure 1A, the lever 18 is in its otherextreme position and it will be noted that it is not in engagement withthe arm A Which is in defrosting position. Thus it is only at one end ofthe range of movement of the lever 18 that the spring 82 loads it duringthe defrosting cycles of operation.

The tension of the spring 82 is adjusted by the screw 84 so that thehigh temperature cut in point of the switch structure can be raised byincreasing the tension or lowered by decreasing the tension.

By providing the defrosting adjustment operated by the range changingknob, this one knob acts as a common means to temporarily adjust theoperating temperature of the switch structure without losing the factorysetting and causes defrosting cycles of operation when set in apredetermined position. The defrosting cycles of operation will continueas long as the knob remains in such position and will be discontinuedwhen it is moved to any of its other positions.

The defrosting position of the knob 16 is preferably at the hightemperature end of the limited movement of travel of the knob, sincewhen so arranged, the knob in defrosting position will cause a slightraising of the low temperature end of the differential of operation ofthe switch structure and a considerable raise in the high temperatureend of the differential of operation. This, in order to obtain adefrosting temperature, makes it possible to obtain it with lessdifferential than if the defrosting position were adjacent the lowtemperature selection end of the travel of the knob.

The knob 16 is used for temperature selection, manual on and off controland reset control after overload cutout operation has occurred. By mypresent invention it is also used for controlling the defrostingoperation and thus it is obvious that I have provided a single controlfor any of the mentioned controlling operations in combination withcontrolling the defrosting operation of the switch structure.

Some changes may be made in the construct on and arrangement of theparts of my device without departing from the real spirit and purpose ofmy invention, and it is my intention to cover by my claims, any modifiedforms of structure or use of mechanical equivalents which may bereasonably, included within their scope.

I claim as my invention:

1. A control mechanism for refrigerators comprising means for startingand stopping operation of the refrigerator to obtain normal cycles ofoperation, means for securing temporary modification of the normalcycles of operation of the refrigerator with the temperature limitsbetween starting and stopping remaining the same, means for obtainingnon-normal cycles of operation of the refrigerator with the temperaturelimits between starting and stopping being changed and common meansmanually settable for securing either said temporary modification of thenormal cycles of operation or said nonnormal cycles of operation.

2. A control mechanism for the o eration of a refrigerator comprisingmeans or starting and stopping the operation of the refrigerator with afixed differential between starting and stopping, means for changing therange for starting and stopping operation and means associated with andrendered operative or inoperative by said last means for temporarilychanging the differential for non-normal cycles of operation of therefrigerator.

3. A control mechanism for refrigerators comprising a cyclicallyoperated movable member, means for adjusting the normal range of saidmember, means in addition to said adjusting means to secure temporarynon-normal cycles of operation of the refrigerator and manuallycontrolled means for rendering said last means effective or ineffective,said manually controlled means also serving to adjust said firstmentioned means.

4. For use with a control mechanism including a cyclically operatedmovable member and adjustable means for adjusting the normal rangethereof, means in addition to said adjustable means for modifying theoperation of a device controlled by said control mechanism to secure atemporary nonnormal operating cycle comprising a resisting memberadapted only upon movement of said adjustable means beyond adjustment ofthe range for normal operation to resist movement of said movable memberfor securing said non-normal cycle of operation.

5. In combination with an automatically movable member and manuallyadjustable means movable between predetermined limits to vary the rangethereof, mechanism for modifying the cycles of operation of saidautomatically movable member comprising a resisting member selectivelymovable to operative and inoperative positions, said manually adjustablemeans being operatively associated therewith to render it operative toso modify said cycles of operation in one position of the manually adustable means and to render it inoperative in all other positions of themanually adjustable means.

6. In combination with an automatically movable member operable throughcycles of operation and having manually adjustable means movable totravel between predetermined li-mits to change the range thereof,mechanism for modifying said cycles of operation comprising a modif ingmember selectively movable to operative and inoperative positions, saidmanually adjustable means being operatively associated therewith torender it operative to so modify said cycles of operation in oneposition of the manually adjustable means at one limit of its limitedpath of travel and to render it inoperative in all other positionsthereof.

7. For use with an automatic control device having an alternatelyoppositely movable member, means to prolong the movement of said movablemember in one direction comprising a spring loaded member to be engagedby said movable member and manually operable means to set and retain itin position to be engaged thereby during the latter part onlyof itsmovement in such direction to prolong movement of the movable memberduring such part of its movement or to set and retain it in positionspaced therea from whereby movement of the movable member is not soprolonged.

8. A control mechanism for refrigerators comprising automatic means forstarting and stopping operation of the refrigerator to obtain normalcycles of operation with the temperature limits between starting andstopping predetermined, overload protection means for non-normallystopping operation of said refrigerator, means for obtaining nonnormalcycles of operation of said refrigerator with the temperature limitsbetween starting and stopping being changed so that the time periodbefore starting is prolonged and common means manually operable forresetting said overload protection means and securing saidnon-normalcycles of operation. 9. A control mechanism for refrigerators comprisingautomatic means for starting and stopping operation of the refrigeratorto obtain normal cycles of operation, control means for starting andstopping said refrigerator independent of said automatic means, meansfor obtaining non-normal cycles of operation of said refrigerator withthe temperature limits between starting and stopping being changed andcommon means manually operable for operating said control means andsecuring said non-normal cycles of operation.

10. A control mechanism for refrigerators comprising automatic means forstarting and stopping operation of the refrigerator to obtain normalcycles of operation, overload protection means for normally stoppingoperation of said refrigerator, control means for starting and stoppingsaid refrigerator'independent of said automatic and overload protectionmeans, means for obtaining non-normal cycles of operation of saidrefrigerator with the temperature limits between starting and stoppingbeing changed and common means manually operable for resetting said'overload protection means, operating said control means and securingsaid non-normal cycles of operation.

11. A control mechanism for refrigerators comprising means for startingand stopping operation of the refrigerator to obtain normal cycles ofoperation, means for securing temporary modification of the normalcycles of operation of the refrigerator with the temperature limitsbetween stopping and starting remaining the same, overload protectionmeans for non-normally stopping operation of said refrigerator, meansfor obtaining nonnormal cycles of operation of the refrigerator with thetemperature limits between stopping and starting being changed andcommon means manually operable for securing said temporary normal cyclesof operation, resetting said overload protection means and securing saidnon-normal cycles of operation.

12. A control mechanism for refrigerators comprising means for startingand stopping operation of the refrigerator to obtain normal cycles ofoperation, means for securing temporary modification of the normalcycles of operation of the refrigerator with the temperature limitsbetween stopping and starting remaining the same, control means forstarting and stopping said refrigerator independent of said rst means,means for obtaining non-normal cycles of operation with the temperaturelimits between stopping and starting being changed and common meansmanually operable for securing said temporary normal cycles ofoperation, operating said control means and securing said non normalcycles of operation at the will of the operator.

13. A control mechanism for refrigerators comprising factory set meansfor starting and stopping operation of the refrigerator to obtain normalcycles of operation, means for securing temporary modification of thenormal cycles of operation of the refrigerator with the temperaturelimits between starting and stopping remaining the same and means forobtaining non-normal cycles of operation of the refrigerator with thetemperature limits between starting and stopping being changed, onelimit being substantially the factory set low temperature and the othermaterlally higher than the factory set high temperature and common meansmanua 1y operable for securing said temporary normal cycles of operationand said non-normal cycles of operation, both at the will of theoperator.

14. A control mechanism for refrigerators comprising means for startingand stopping operation of the refrigerator to obtain normal cycles ofoperation, means for securing temporary modification of the normalcycles of operation of the refrigerator with the tem perature limitsbetween stopping and starting remaining the same, means for obtaining adefrosting cycle of operation of the refrigerator with the temperaturelimits between stopping and starting being changed for defrostingpurposes and common means manually operable for securing said temporarynormal cycles of operation and securing said defrosting cycle ofoperation.

15. A control mechanism for refrigerators comprising means for startingand stopping operation of the refrigerator to obtain nor:- mal cycles ofoperation, means for securing? temporary modification of the normalcycles of operation of the refrigerator with the temperature limitsbetween stopping and starting remaining the same, means for obtaining adefrosting cycle of operation of the refri erator with the stoppinglimit remaining su stantially the same and the starting limit beingmaterially raised for defrosting purposes and common means manuallyoperable for securing said temporary normal cycles of operation andsecuring said defrosting cycle of operation.

Des Moines, Iowa, October 24, 1932.

MALCOLM E. HEN NING.

